Recent advances in cantilever-based force detection have allowed detection of forces below an attonewton. We have applied this capability to the study of dissipation and fluctuations in nanometer-scale systems. Our work is largely motivated by our effort to extend magnetic resonance force microscopy (MRFM) to single-spin sensitivity, where we have been confronted with a variety of unanticipated noise issues. Phenomena that we have studied include magnetic moment fluctuations in nanoscale ferromagnets, non-contact friction and force fluctuations near surfaces, and increased electron spin relaxation rates observed when closely monitoring electron spins by MRFM. The enhanced spin relaxation rate is believed to be caused by Rabi frequency magnetic noise that is generated by thermal vibrations in high order cantilever modes. Overcoming these various noise issues will be key to achieving single-spin quantum readout.
This work was performed in collaboration with H. J. Mamin, R. Budakian, B. Chui, B. Stipe and C. S. Yannoni. We thank ONR and the DARPA Mosaic program for financial support.